UPS and PSU help

[Righteous]

Hi Guys,

I'm currently trying to decide on a UPS for my system at home. I've recently built a machine that has a 1200W PSU. My question is, do you need a UPS that can supply 1200W of power. It seems like an obvious yes to me, but wanted to check that I'm not over doing it as the price difference between 1000W, above and below, is pretty significant.

I'm currently looking at this. http://www.cpsww.com.au/products/ups_sy ... cdrt2u.htm" onclick="window.open(this.href);return false;

Is that overkill for a dual Xeon with 2 large monitors and a shit tone of HDDs?

[ysu]

I'd say no, unless your computer actually pulls full power when runs on max, and you want your computer to run on max when you've no AC power!
I'd get a meter to measure the actual power drawing at the plug under load. A HDD won't pull too much power, the computer you quoted is prolly drawing 400W-500W max (gfx card setup may change that).
Although depending on its age, the PSU might be rather inefficient and pull a lot more than necessary.

Edited: the two monitors may add ~60W each if LCDs

[wobblysauce]

Depends on what you want to do with it, Power replacement till it comes back on or just so you can safely save and shout down.

Both monitors do not need to be plugged in, could just do the one.
For best efficiency normally the wattage total is 80% of Psu rating, but depends on how the system is built.

You just need one that can cover the base load on the circuitry, battery's can be upgraded to something bigger later or more boxes.

[ysu]

What you're talking about wobbs, as the efficiency (of 80%) is the maximum you can draw from the PSU if it's drawing full power from the wall, IMHO.
The situation is reverse here, and it's quite likely that the PSU is never used to its maximum capacity (which is a wise thing to do I've heard, as it would shorten its life).

by the way here's something intersting, a UPS calculator
http://www.refurbups.com/UPS-Sizing-Calculator-2" onclick="window.open(this.href);return false;

Edit: it seems to work simply on the 'maximum' value, which is understandable - they want to sell the biggest PSU to you
But yeah, if you want to be on the absolute safe side, that's what you'll want to buy I reckon.

[Shonky]

Not sure it helps Righty but years ago I had a 1000VA UPS, and it used to be able to run my system (P4 2.4GHz, 8800GT and 27" Dell LCD from memory) for about 15 minutes just surfing the net before the low battery alarm went off, but if I was gaming it would have been 5 minutes tops.

It depends on what you need it to do, is it just to give you enough time to save what you are working on at the time and shut down because of an unreliable street supply, or is it to keep the system running for an extended amount of time while rendering video/gaming, if you need the former a 750-1000VA UPS should suffice, but if it's the latter expect to pay huge money. In a nutshell, the longer you want the system to stay up, the more money it will cost.

[ysu]

hm...as far as i know there's two measurements/specs we're talking about here.
Watts and Volt-Amperes , W and VA

The watts specs is the "what you can draw" without damaging the UPS, the VA is "how long will it last".

The question was about the Watts here I think.

Happy to be corrected.

as far as i know the point of a battery-powered UPS is to bridge minute problems/brownouts and allow a safe shutdown in blackouts, it's pretty much never to bridge serious power outages. That should be done with a generator.

[Shonky]

Sorry ysu, the electrician in me has clouded the issue just because of force of habit, when talking about UPSs the correct output rating for them is VA (Volts X Amps), because watts on AC also has a "power factor" component to deal with as well, if you have too much spare time and want to learn about power factor go for it, but for the sake of this thread we should probably just consider VA and watts to be one and the same.

[ysu]

Sorry ysu, the electrician in me has clouded the issue just because of force of habit, when talking about UPSs the correct output rating for them is VA (Volts X Amps), because watts on AC also has a "power factor" component to deal with as well, if you have too much spare time and want to learn about power factor go for it, but for the sake of this thread we should probably just consider VA and watts to be one and the same.

Sure but it remains two separate issues, isn't it? How much power you can draw at once (W) and how long it will last when drawing power from it (VA) - or is that incorrect?
I've read about power components before, and it seems they recommend estimating with a .6-.7 multiplier on AC - but I thought it was still a separate measurement. Fark it's been too long since school

[Righteous]

Hi guys, thanks for the input. Basically, I want to be able to save and shut it down. Probably about 5 minutes max.

The machine is running 2x Xeon 8 core CPU's (16 cores total) a Titan GPU, 2x SSD drives (bugger all power there I'm sure), a PCIe Blackmagic card (to send to broadcast monitor) 8x WD spinny HDDs and the 2 monitors are big Dell 27inch ultrasharp ones. I would think it's pretty power hungry, but I guess there's not really a need to plug everything into UPS. I can just keep monitors and speakers on a smaller surge protector. The PSU is a new Corsair one which should be pretty efficient.

I might do as ysu has said and get a meter to work out what it's actually drawing.

[wobblysauce]

Got mine from a Local company in Dandenong, Upsonic.

DOMESTIC/SME 2000VA, the gaming models are the same but have a few extra leds and a few stickers and cost more. Battery's have lasted about 3yrs avg, depending on usage.

Righteous, if it is also work related cost you could get an industrial UPS and have even longer backup times.

Speaking about that got to look at getting some more or do the marine, deep-discharge batteries mod, for even longer sessions.

Not that saying the 12hrs on the Hot New Years eve day Brownouts is short. Set mine for auto shutdown when at 10% left and it has never shut down while I have been gaming on it, and there has been plenty of spikes and black outs from 5-30mins.

As you would know that saving your work and shutting down, only just have the power come back on just as it starts to shut off is annoying.


The selection chart is getting on in years eg. only up to 21inch screens more options for choice, but more then the one ysu linked.
http://www.upsonic.com.au/selecting-a-ups.php" onclick="window.open(this.href);return false;

Or you could go cheap and find a used/broken(flat battery's normally) UPS of any sort and get your own battery's put in.

[Sarsippius]

I have an Eaton 5110 700VA and have my main pc (Athlon II X4, HD 6850, 1xSSD, 1xHDD), my 2xHDD Atom NAS and 1x 30" Monitor all plugged into it. I think you might get by with less than you think.
It seems this model is no longer sold but there's a newer model that looks almost the same
http://powerquality.eaton.com/Products- ... aspx?cx=22" onclick="window.open(this.href);return false;
Like mine it also has three surge protected sockets as well as the three battery powered sockets, the 1200VA/720W version would probably do you and seems to go for about $250. The 1600/960 is only $50 more.